Spoilers for Sonic 3 obviously

Act 1: Beginnings

Ok so movie begins with mysterious code on the screen, with basic directives, orders to eliminate Sonic the Hedgehog

We see a similar scene to the end of Sonic 3, but from Metal Sonics point of view.

The screen pans out, revealing it was being viewed by someone, that someone is revealed to be a miraculously living Robotnik, alongside an army of badniks and on top of a throne.

We cut back to Sonic, who meets Amy and questions who she is and where she came from.

Amy reveals that she was sent by GUN from a future where everything is in ruin and Robotnik is in charge, and Sonic disappeared/died, remembered as a great hero (and who Amy is a huge fangirl of) much to Sonics bewilderment.

Sonic goes back to his home without her, unsure if he can trust Amy where Tails, Knuckles, Tom, and Maddie are waiting for him.

It's revealed that Amy was actually not far behind Sonic, moving pretty fast herself, and Sonic, impressed, decides to let her join if she can keep up

Insert silly race sequence, Amy trips up, not knowing the environment as well as Sonic does, and in typical Amy fashion, is deeply impressed and infatuated by his mastery of his speed.

They end up back at Sonics home, and Sonic explains who Amy is and what she's here for. Tom and Maddie aren't even surprised that Sonic has found another friend and is already about to head on another adventure. Tails and Knuckles meet her, Tails is a bit scared of her strength, and Knuckles likes her tenacity.

Act 2: Rising Tension

Sonic and the gang head off to try to go to the future, but Amy reveals that she doesn't know to get back to the future, she was just sent back to warn them.

They go to GUN to try and figure out how to get to future.

The Conmander lady from the last movie is hesitant to help after Sonic 3, and thinks that they're just trying to infiltrate GUN because they want something.

Amy proves her wrong with some kind of tech that is something only GUN would have access to, and they decide to help them

They find a way to travel through time using Chaos Energy, however, they don't have the Chaos Emeralds after Sonic 3, and they realize that they need to search for the Emeralds.

GUNs base is attacked suddenly, and it's revealed that more Metal Sonics have been sent to destroy GUN and Sonic again with Robotnik inside a mech alongside them.

Sonic, his friends, and GUN try to fight, but are overwhelmed by the Metal Sonics as well as Robotniks advanced technology.

The group is saved by a sudden burst of energy, and the mech is torn apart by something moving too quick to see.

Sonic realizes who it is through the plot convenient cloud of dust and debris

It is revealed that Shadow was the one who saved them, and that Robotnik inside the mech was just a doll, spitting out lines.

Sonic catches Shadow up on what happened and what they're doing now.

Shadow agrees to help out

Ok so the other parts were gonna be just as long but I got tired so have this instead

The group goes on a mission to find the emeralds

They fight Metal Sonics and badniks on the adventure, also trying to get the emeralds.

They collect all 7, and Sonic and Shadow use Chaos Control to open a portal in time.

Before they can enter, Robotnik comes through the portal with his badniks and they go to steal the emeralds after Sonic collect all of them

Shadow, still being kinda edgy, decided to just take out Robotnik, and throws a punch at him, but it gets caught by his hand

Robotnik transforms, revealing he isn't actually Robotnik, but Neo Metal Sonic, who was created by Agent Stone as a tribute to Robotnik to enforce his will, and became obsessed with beating Sonic so he could take his place.

He kicks the teams ass, using their data, which he copied, matching them all blow for blow, and exceeding their power.

Using Knuckles' biodata he reforms the Master Emerald, and takes it, as well as Amy back to the future, taunting Sonic for being too weak for him to be the real Sonic.

Sonic and his gang say quick goodbyes to Tom, Maddie and GUN and hop into the portal before it closes

They see the "bad future" and wonder what happened to the place, Sonic is disturbed by what happened to the world he cared for, and Shadow by what happened to the world Maria cared for.

Continued (it was still too long)

They traverse the ravaged world and see cities, transformed into wastelands, filled with machines and neon lights

Sonic and his friends destroy the machines around the city and are seen and praised as people recognize him as the hero who died fighting Neo Metal Sonic

Neo Metal Sonic shows up with the Master Emerald, and crushes Sonics team even harder than before with the Master Emeralds power

Neo Metal absorbs the emerald and transforms, becoming Metal Overlord, and travels back in time, to begin the takeover in the past so that the future they are in can exist.

Sonic and his group follow, and find him on top of a giant airship thingy like the games

Shadow, knowing they can't take him in their current states, flies into his core or sumn and knocks the Master Emerald out of him, but the energy it takes to do so is too much for him and it knocks him out

Sonic, Tails, and Knuckles, transform into super forms, and fight Metal Overlord

What I'm Made Of Remix

There's a big battle, with Sonic and his friends coming out on top

They save Amy and Shadow, and they gtfo before explosion thing

They go back to the future to find it changed, now a "good future", peaceful and harmonious because of Sonics efforts

They prepare to leave Amy, but she decides to come back with them and to go work for GUN

Shadow goes on some side quest of his own, potential spinoff stuff

Movie ends with a special scene of the future transforming once again, turning to flames and fire with a new hero showing up as the change occurs:

Silver the Hedgehog.

Anyways that's the end byeeeeeee